JP2014176220A - Electrical angle adjustment method for motor and axial vibration inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultra-high speed motor capable of correcting a delay of a sensor signal during high-speed rotation by suppressing axial vibration caused by imbalance of a rotor.SOLUTION: By comparing a position sensor signal that detects an edge of a tooth section of a sensor target mounted on the rotor side of a motor to a phase of an induced voltage under a non-energized state, an offset amount between a mechanical angle and an electrical angle signals obtained from the position sensor signal are stored in a memory for each rotational speed, and the position sensor signal is corrected based on the stored offset amount.

Description

  The present invention relates to an electric angle adjustment method and a shaft vibration inspection method for correcting a deviation between an electric angle of a motor and a mechanical angle obtained from a rotation angle sensor in an electric motor controlled using an inverter.

  AC motors, in particular synchronous motors, need to control the current supplied based on the magnetic pole position, but the mechanical angle for detecting the electrical angle representing the magnetic pole position of the motor and the mechanical rotation angle of the motor is physically Therefore, a technique for driving the electric motor by correcting such a deviation is known.

That is, in an electric motor control device that controls an electric motor using a position sensor that detects a magnetic pole position of an electric motor rotor, a phase based on the position sensor is caused by a physical misalignment (attachment error) that occurs when the position sensor is attached. A deviation occurs from the actual magnetic pole position. As a result, the control characteristics are deteriorated, and there is a possibility that a desired torque and efficiency cannot be obtained, for example.
In addition, unlike a general motor, for example, in an ultra-high speed motor of 70,000 rpm or more, there is a delay time from when the sensor itself detects the rotational position signal until it is input to the control microcomputer. It is difficult to correlate the phase based on the sensor and the actual magnetic pole position (electrical angle phase).

  In addition, in an ultra-high speed motor, if there is an imbalance in the rotor of the motor, not only the problem that the desired torque cannot be obtained by the motor, but also the shaft vibration may increase during high-speed rotation and damage the bearing part. There is. For this reason, it is common to assemble to the stator after adjusting the mechanical balance on the rotor side of the electric motor. However, the magnetic attraction generated between the rotor and the stator after being assembled to the stator side. Since stress is generated by force or the like, it is desirable that the final balance inspection is performed with the rotor assembled to the stator.

  In view of such a background, for example, in Patent Document 1, in order to correct the phase of the position sensor, the point where the motor winding and the magnetic pole position coincide with each other from the detected magnetic pole position value and the phase voltage of the armature, and the encoder output signal In this example, an offset adjuster that performs an adjustment operation using the difference between the two as an offset amount is provided.

  Patent Document 2 calculates the sum of two types of torque generated by applying two types of currents of different polarities to the stator, and sets the electrical angle and mechanical angle as the offset value at the point where the sum is zero. What adjusts the offset is shown.

  In Patent Document 3, a rotor provided with a plurality of tooth portions is attached, the tooth portions are sandwiched between them, and optical sensors are arranged at positions facing each other to detect axial vibration. It is shown.

  Japanese Patent Laid-Open No. 2004-228561 discloses a method in which the balance of the motor is adjusted by driving using a dedicated inverter for balance correction in addition to the inverter that is actually driven in a state where the stator is assembled to the rotor. Has been.

JP 2003-79185 A Japanese Patent Laid-Open No. 10-262397 JP 2010-185838 A JP 2007-183203 A

  Even if the offset amount due to the error in mounting the phase of the position sensor and the phase of the electrical angle is adjusted as in Patent Document 1 described above, if the rotational speed increases, the sensor signal signal may be corrected even if the offset amount is corrected. There is a problem that desired control characteristics cannot be obtained due to a delay error or the like.

  In addition, in Patent Document 2, it is effective for an electric motor that operates only at a predetermined rotational speed. However, in an electric motor that performs control adjustment at various rotational speeds, the number of points for control adjustment increases, and the delay of the sensor signal is increased. Therefore, there is a problem that desired control characteristics cannot be obtained.

  Furthermore, since the thing of patent document 3 is equipped with an optical sensor in opposition and detects axial vibration, when there is a difference in the processing speed of the facing sensor, the problem that axial vibration cannot be measured accurately. In addition, when there is an error in sensor mounting, there is a problem that shaft vibration cannot be measured accurately.

  In Patent Document 4, the balance of the electric motor is corrected using a dedicated motor driver. However, since power is supplied using a dedicated balance correcting driver, it is necessary to prepare a motor driver for inspection. There is a problem that there is. As described above, there is a problem that the desired control characteristic cannot be obtained unless the offset amount of the electrical angle and the mechanical angle is accurately taken, and storing the characteristic of the motor to be inspected by the dedicated motor driver is a complicated system. Will be.

  The present invention has been made to solve the above-described problems, and can adjust the electrical angle of an electric motor that can be controlled in response to sensor signal delays at various rotational speeds without complicating the system. A method and a shaft vibration inspection method are provided.

An electric angle adjustment method for an electric motor according to the present invention includes a sensor target provided on a rotor side of an electric motor and having a tooth part, and a rising or falling edge of a tooth part of the sensor target provided on a stator side of the electric motor. A position sensor for detecting an edge, and after increasing the number of revolutions with the electric motor in an operating state, detecting an induced voltage of the electric motor when the electric motor is in a non-energized state, and detecting the induced voltage and the position sensor And the difference between the mechanical angle calculated from the position sensor, the magnetic pole position of the rotor and the electrical angle obtained from the winding of the stator, as an offset amount,
The amount of offset is calculated by varying the number of revolutions of the motor, the amount of offset is stored in a memory, and the motor is controlled based on the amount of offset stored in accordance with the number of revolutions during operation of the motor. It is characterized by doing.
Further, the shaft vibration of the rotor is determined based on the offset amount calculated using the electric angle adjustment method of the electric motor.

According to this invention, the mechanical angle obtained from the sensor signal can be obtained by comparing the position sensor signal for detecting the edge of the tooth portion attached to the rotor portion of the electric motor with the induced voltage in a state where current is not applied. By taking an offset of the electrical angle signal and providing a map for each rotation speed instead of only one point, not only the offset caused by the mounting error between the mechanical angle and electrical angle, but also the sensor response delay and communication delay It is possible to provide an offset map in consideration of the above. Further, since the magnitude of the shaft vibration can be grasped by comparing the offset amount for each edge, the offset adjustment can be performed simultaneously with the shaft vibration inspection.

It is a schematic diagram which shows the principal part structure of the electric motor which concerns on Embodiment 1 of this invention. It is a block diagram which shows the control circuit of the electric supercharger which concerns on Embodiment 1 of this invention. It is a characteristic view which shows the sensor offset characteristic which concerns on Embodiment 1 of this invention. It is a flowchart for demonstrating the electrical angle adjustment method and shaft vibration test method of the electric motor which concern on Embodiment 1 of this invention. It is a schematic diagram which shows the principal part structure of the electric motor which concerns on Embodiment 2 of this invention.

Embodiment 1 FIG.
Hereinafter, the present invention will be described with reference to the drawings as embodiments.
FIG. 1 is a schematic diagram showing the configuration of the main part of an electric motor which is one of the preferred embodiments of the present invention. In order to make the explanation easy to understand, a two-pole pair three-phase synchronous motor is taken as an example. There are no restrictions on the applied motor.

  In FIG. 1, an electric motor 1 includes a stator 2 for passing a three-phase current, a two-pole pair of rotors 3 that are attached to a rotating shaft so as to face the stator 2, and the number of pole pairs of the rotor 3. The rotation target has the same number of teeth as the rotation target, and is attached to one end of the rotation shaft and the stator 2 side, and detects the rising or falling edge of the tooth portion of the sensor target 4. And a position sensor 5 such as a hall sensor.

  Here, the rotor 3 and the sensor target 4 are fixed by being press-fitted into the rotating shaft or tightened with screws or the like at a predetermined mounting angle, and the balance adjusted with these assemblies is attached to the stator 2. It is desirable to assemble. That is, by performing balance adjustment with the assembly of the rotor 3 and the sensor target 4 in advance, in the state where these are assembled to the stator 2, only by examining the shaft vibration due to unbalance at the time of assembly. Balance adjustment can be completed. Further, the shaft vibration can be suppressed and damage to the bearing can be prevented as compared with the case where it is assembled to the stator 2 in a state where balance adjustment is not performed on the rotor 3 side.

  When the sensor target 4 and the rotor 3 are fixed, it is difficult to attach the mechanical angle by the sensor mechanically attached to the electrical angle at the magnetic pole position without error, but it is not possible to attach with the highest possible accuracy. Is possible. Therefore, by setting the electrical angle and the mechanical angle to some extent at the time of assembly, it becomes possible to ensure a certain level of control performance in the process of finally setting the offset value of the electrical angle and the mechanical angle.

  Further, the position sensor 5 measures the distance from the sensor target 4 by measuring the magnetic flux, and detects the moment when the edge of the sensor target 4 passes, but may include a plurality of position sensors 5. It becomes possible to detect the offset amount of the electrical angle and the mechanical angle with higher accuracy than the case.

  Next, the control operation of the electric supercharger to which the electric motor shown in FIG. 1 is applied will be described with reference to FIG. 2 which is a functional block.

  In FIG. 2, the electric supercharger 11 includes an electric motor 1 including a position sensor 5, a current controller 12 for controlling the electric motor 1, a power converter 13, a phase generator 14, and the like. 12, the phase generator 14 is a functional block calculated by a microcomputer, and the power converter 13 is a circuit block mainly including a switching element. Other configurations are omitted.

  Here, the current controller 12 receives a rotation speed command, a voltage sensor signal indicating the battery voltage, and an output signal of the position sensor 5 from a host controller (not shown), and represents the magnitude of the current that is supplied to the motor 1 3 A phase calculation is performed for the phase duty command value and the voltage phase indicating the energization timing.

  Since the voltage phase is calculated using an electrical angle, it is necessary to remove the electrical angle and the mechanical angle offset in order to match the actual mechanical angle, and this is calculated by the phase generator 14. As a result, the electric motor 1 can be operated with high efficiency except by adding the offset value.

  Next, the relationship between the signal of the position sensor 5 and the induced voltage generated in the stator winding of the electric motor 1 will be described. Since the signal of the position sensor 5 is output according to the magnetic pole position of the sensor target 4 attached to the rotor 3 of the electric motor 1, the signal of the position sensor 5 and the induced voltage generated in the stator winding can correspond. For example, the rise and fall of the signal of the position sensor 5 ideally match the rise and fall of the induced voltage, respectively. However, when there is an attachment error of the position sensor 5, a deviation occurs. In general, since there is a limit to the assembly accuracy, the electrical angle and the mechanical angle have a certain offset.

  If the rotational speed of the normal electric motor 1 is used, it is possible to use the sensor signal with high accuracy by correcting this constant offset value. With respect to the rotating electric motor 1, even if the offset correction of the attachment position is performed, a sensor signal is delayed when operating in the high-speed rotation region, so that it is difficult to operate with high efficiency.

  For this reason, in the first embodiment, the phase generator 14 is provided with an offset value corresponding to the rotational speed of the electric motor 1 in advance as a map, and the electric motor 1 is controlled according to this output, so that the delay of the sensor signal is prevented. Even if it corrects, it becomes possible. A method for calculating the offset value for each rotation speed will be described later.

  Next, the relationship between sensor offset and shaft vibration will be described with reference to FIG.

  3 shows the electrical angle of the electric motor 1 and the offset value for each rotational angle of the mechanical angle obtained by the position sensor 5 in the first embodiment. Ideally, the offset for each rotation speed is Real_Offset in the figure. At this time, the offset value deviating for each rotation number means that there is a delay in the sensor signal, and when the rotation number increases, a deviation occurs in the offset value.

  However, in practice, the electric motor 1 may resonate at a certain number of revolutions when there is some unbalance remaining after balance adjustment. Therefore, when the offset map is calculated by detecting two rising edges in one rotation of the rotor 3, it is calculated from the first offset Offset1 calculated from the first edge and the second edge as shown in FIG. Two offset maps are calculated as in the second Offset2. The difference between the two offset maps increases as the unbalance amount increases.

Therefore, in the present invention, it is possible to inspect the shaft vibration accompanying the unbalance while adjusting the offset between the electrical angle and the mechanical angle using the offset map.
For example, an upper limit value Offset_u and a lower limit value Offset_l are provided for the first offset Offset1 and the second offset Offset2, respectively. It becomes possible.

  Next, specific operations relating to the electric angle adjustment method and the shaft vibration inspection method of the motor will be described based on the flowchart of FIG.

In the figure, first, in step S1, it is determined from the signal supplied to the stator windings of the electric motor 1 whether or not the rotational speed is equal to or greater than a predetermined value. At the time of adjustment, the offset map is driven using a target offset when the rotor 3 and the sensor target 4 are attached. First, the electric motor 1 is driven to a predetermined rotational speed or more using the target offset. In general, when the electric supercharger 11 is rotated at a low speed, the influence of its own cogging torque and the alignment function of the bearing are lowered, so that the rotation becomes unstable.
That is, when the motor 1 is rotating at a low speed, it is not suitable for determining the relationship between the mechanical angle and the electrical angle. If the rotational speed is not equal to or greater than a predetermined value, the adjustment is terminated and Wait and go to the next step.

  Next, when the number of rotations exceeds a predetermined value, the energization of the electric motor 1 is stopped. (Step S2) In the state where the electric motor 1 is energized, since the relationship between the induced voltage generated in the electric motor 1 and the offset of the position sensor 5 is not uniquely determined, the offset is not corrected.

  Next, an offset between the electrical angle and the mechanical angle is calculated from the induced voltage generated in the electric motor 1 and the first edge signal and the second edge signal of the position sensor 5 detected by passing the edge of the sensor target 4. (Step S3)

Next, the difference between the first offset value and the second offset value calculated in step S3 is taken. (Step S4) At this time, if the magnitude of the difference is greater than or equal to a predetermined value at a predetermined number of revolutions as an inspection, it is determined by the inspection that the shaft vibration is large, and the process is terminated without storing the offset value. .
This determination can be made in the final stage by reading the memory offset value stored in the microcomputer and not having an offset value corresponding to the rotational speed.
The electric motor 1 determined to have a large shaft vibration may return to step S1 by, for example, shaving a shaft or the like, or return to step S1. Alternatively, for the motor 1 having a large shaft vibration level, the stator 2 and the rotor. 3 may be disassembled to perform each inspection, and the process may return to step S1 after reassembly.

Next, an average of the first offset value and the second offset value is calculated as an offset value (step S5), and the offset average is stored in the memory of the microcomputer as a phase correction amount setting. (Step S6)
Such steps are repeated while changing the number of revolutions, and the offset value for each number of revolutions is stored in the memory and used for the calculation of the phase generator 14.

In the above embodiment, the offset value is not stored when the difference is greater than or equal to the predetermined value in step S4. However, the offset amount is stored as it is, and the stored value is read out. It is also possible to inspect shaft vibration.
Although not specifically mentioned in the present embodiment, when the sensor delay is a constant value, the characteristics are not taken at all the rotational speeds as shown in FIG. 3, for example, three points such as 90000 rpm, 60000 rpm, 30000 rpm, Thus, the offset map can be approximated by an interpolation calculation or the like. By doing so, it is possible to see the number of rotations to be noticed, and by reducing the number of measurement points, it is possible to further reduce the inspection man-hours and obtain the same effect.

Further, when it is known in advance that the resonance point is within the operating rotational speed range of the electric motor 1, it is possible to confirm the damping effect when the rotor 3 is assembled to the stator 2 and inspected. For example, in general, when having a resonance rotational speed determined by the rigidity of the rotor 3 or the like, it is fixed via a rubber damper or the like in order to expect a damping effect when assembled to the stator 2. Whether the damping effect can be obtained can be measured only when the rotor 3 and the stator 2 are assembled.
Therefore, the damping effect can be confirmed even in the case of having resonance by inspecting the shaft vibration in the state where the rotor 3 and the stator 2 of the electric motor 1 are assembled as in the present invention.

  According to the first embodiment as described above, not only the offset correction caused by the mechanical deviation between the mechanical angle obtained from the sensor signal of the electric motor 1 and the electrical angle signal but also the sensor response delay and communication delay are taken into consideration. An offset map can be provided. As a result, it is possible to efficiently operate the electric motor 1 of the electric supercharger even during the ultra-high speed rotation. Further, since the magnitude of the shaft vibration can be grasped by comparing the offset amounts for each of the plurality of edges, the shaft vibration can be inspected together with the offset adjustment.

  In the first embodiment, the offset map corresponding to the rotation speed of the electric supercharger is provided. However, when the offset gradient for each rotation speed is large, it is determined that the sensor delay is large and the sensor offset is set. The calculation of the quantity may be stopped and the inspection product may be ineligible. For example, when the delay of the sensor signal is large, the offset gradient for each rotation speed increases. By using a position sensor having an offset gradient for each predetermined number of revolutions, it is possible to remove those with abnormal sensor characteristics.

Embodiment 2. FIG.
The second embodiment of the present invention will be described below.
In the second embodiment, as shown in FIG. 5, a compressor impeller 20 that compresses gas is disposed on the opposite side of the sensor target 4 attached to the rotor 3 of the electric motor 1.

  Under such a configuration, the specific offset adjustment is the same as that of the first embodiment. However, when the shaft vibration is large and it is necessary to adjust the balance again, the compressor impeller 20 has a compression characteristic. It is difficult to adjust the balance. On the other hand, the sensor target 4 is suitable for balance adjustment because there is no influence on the characteristics other than the edge portion.

  Therefore, when the ultrahigh-speed motor is applied to the electric supercharger in this way, the balance adjustment is performed by the sensor target 4 by arranging the sensor target 4 at one end of the rotor 3 and the compressor impeller 20 on the opposite side. This makes it possible to easily adjust the balance while ensuring the compression performance of the electric motor 1 and the compressor impeller 20.

  Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and can be appropriately modified and omitted within the scope of the invention.

1: electric motor, 2: stator, 3: rotor, 4: sensor target,
5: Position sensor, 11: Electric supercharger, 12: Current controller,
13: Power converter, 14: Phase generator, 20: Compressor impeller

An electric angle adjustment method for an electric motor according to the present invention includes a sensor target provided on a rotor side of an electric motor and having a tooth part, and a rising or falling edge of a tooth part of the sensor target provided on a stator side of the electric motor. It has a position sensor that detects edges,
After the pre-Symbol motor increases the number of rotation in the operating state, detects the induced voltage of the motor when the motor is in a non-energized state, the relationship between the signal of the induced voltage and the position sensor, the While calculating the difference between the mechanical angle calculated from the position sensor, the magnetic pole position of the rotor and the electrical angle obtained from the winding of the stator as an offset amount,
The amount of offset is calculated by varying the number of revolutions of the motor, the amount of offset is stored in a memory, and the motor is controlled based on the amount of offset stored in accordance with the number of revolutions during operation of the motor. To do ,
An offset gradient is calculated from the offset amount for each rotation speed, and when the offset gradient is equal to or greater than a predetermined value, the calculation of the sensor offset amount is stopped .
Further, the shaft vibration of the rotor is determined based on the offset amount or the offset gradient calculated using the electric angle adjustment method of the electric motor.

Claims (6)

A sensor target provided on the rotor side of the electric motor and having a tooth part; and a position sensor provided on the stator side of the electric motor and detecting a rising edge or a falling edge of the tooth part of the sensor target;
After increasing the number of revolutions with the motor in an operating state, the induced voltage of the motor is detected when the motor is in a non-energized state, and the position is determined from the relationship between the induced voltage and the signal of the position sensor. While calculating the difference between the mechanical angle calculated from the sensor, the magnetic pole position of the rotor and the electrical angle obtained from the winding of the stator as an offset amount,
The amount of offset is calculated by varying the number of revolutions of the electric motor, these offset amounts are stored in a memory,
An electric angle adjustment method for an electric motor, wherein the electric motor is controlled based on the offset amount stored in accordance with the rotational speed during operation of the electric motor.   2. The electric angle adjustment method for an electric motor according to claim 1, wherein the calculation of the offset amount is performed at a predetermined rotation speed or higher when the energization is stopped.   The electric angle adjustment method for an electric motor according to claim 1, wherein the tooth portion of the sensor target has at least two poles.   The offset gradient for each rotation speed is calculated from the offset amount for each rotation speed, and when the offset gradient for each rotation speed is equal to or greater than a predetermined value, the calculation of the sensor offset amount is stopped. The electric angle adjustment method for an electric motor according to any one of claims 1 to 3.   5. The electric angle adjustment method for an electric motor according to claim 1, wherein a sensor target is arranged on one end side of the rotor and a compressor impeller is arranged on the opposite side of the electric motor. A method for inspecting a shaft vibration of an electric motor using the electrical angle adjustment method according to any one of claims 1 to 5, wherein a shaft vibration of a rotor is determined based on the detected offset amount.